In, for example, automobiles, wire harnesses (groups of electrical wires) in which a plurality of electrical wires are bundled together are laid and a plurality of electrical devices are electrically connected to each other by the wire harnesses. Wire harnesses are connected to electrical devices, or wire harnesses are connected to each other, via connectors provided to both the wire harnesses and devices. For such an electrical wire, an insulated electrical wire formed by covering a core wire portion (a conductor portion) with an insulator is used. For example, a crimping terminal is connected to an end portion of the core wire exposed by peeling away the covering on the insulated electrical wire, and a connector is then attached via the crimping terminal.
The crimping terminal is made of copper, and thus in the case where the electrical wire is changed from a copper electrical wire to an aluminum electrical wire, the crimping terminal and the electrical wire result in dissimilar metal contact. As such, the metals will easily corrode if water enters. Patent Documents 1 and 2, which disclose structures in which an intermediate cap or a waterproof tube is provided between an open-barrel crimping terminal and an aluminum electrical wire, can be given as examples of techniques for improving watertightness, but these techniques have difficult aspects such as a complicated manufacturing process. Thus to avoid these difficult aspects, the inventors of the present application have proposed a closed-barrel crimping terminal that is intended to simplify corrosion resistance as well as being mass-producible while suppressing production costs (Patent Document 3).